And then my imagination is kindled by the Mouth of Sauron himself. Did he undertake real diplomatic missions to the East and South, and is that how Sauron got his allies/cronies from those areas? Was there a whole stable of Mouths of Sauron, or just one? And how much did he really know about Gandalf, because I think he dismisses him a little too readily, as if he's afraid of him and doesn't want to show it.

“‘Name the terms,’ said Gandalf steadily, but those nearby saw the anguish in his face, and now he seemed an old and wizened man, crushed, defeated at last. They did not doubt that he would accept.”
[my bolds]

‘Then about a year ago a messenger came to Dáin, but not from Moria – from Mordor: a horseman in the night, who called Dáin to his gate. The Lord Sauron the Great, so he said, wished for our friendship. Rings he would give for it, such as he gave of old. And he asked urgently concerning hobbits, of what kind they were, and where they dwelt. “For Sauron knows,” said he, “that one of these was known to you on a time.”

‘At this we were greatly troubled, and we gave no answer. And then his fell voice was lowered, and he would have sweetened it if he could. “As a small token only of your friendship Sauron asks this,” he said: “that you should find this thief,” such was his word, “and get from him, willing or no, a little ring, the least of rings, that once he stole. It is but a trifle that Sauron fancies, and an earnest of your good will. Find it, and three rings that the Dwarf-sires possessed of old shall be returned to you, and the realm of Moria shall be yours for ever. Find only news of the thief, whether he still lives and where, and you shall have great reward and lasting friendship from the Lord. Refuse, and things will not seem so well. Do you refuse?”

‘At that his breath came like the hiss of snakes, and all who stood by shuddered, but Dáin said: “I say neither yea nor nay. I must consider this message and what it means under its fair cloak.”

‘“Consider well, but not too long,” said he.

‘“The time of my thought is my own to spend,” answered Dáin.

‘“For the present,” said he, and rode into the darkness.

‘Heavy have the hearts of our chieftains been since that night. We needed not the fell voice of the messenger to warn us that his words held both menace and deceit; for we knew already that the power that has re-entered Mordor has not changed, and ever it betrayed us of old. Twice the messenger has returned, and has gone unanswered.

Gandalf would ascend into the tower, to discuss deep things beyond their comprehension in the high chambers of Orthanc. The door would be closed, and they would be left outside, dismissed to await allotted work or punishment. Even in the mind of Théoden the thought took shape, like a shadow of doubt: ‘He will betray us; he will go – we shall be lost.’

Then Gandalf laughed. The fantasy vanished like a puff of smoke.

The horses were uneasy. But the king sat upon Snowmane, motionless, gazing upon the agony of Minas Tirith, as if stricken suddenly by anguish, or by dread. He seemed to shrink down, cowed by age. Merry himself felt as if a great weight of horror and doubt had settled on him. His heart beat slowly. Time seemed poised in uncertainty. They were too late! Too late was worse than never! Perhaps Théoden would quail, bow his old head, turn, slink away to hide in the hills.

‘S is for Sauron,’ said Gimli. ‘That is easy to read.’

‘Nay!’ said Legolas. ‘Sauron does not use the elf-runes.’ [Except he did on the One Ring.]

‘Neither does he use his right name, nor permit it to be spelt or spoken,’ said Aragorn. ‘And he does not use white. The Orcs in the service of Barad-dûr use the sign of the Red Eye.’ He stood for a moment in thought. ‘S is for Saruman, I guess,’